Tremendous quantities of valuable text data are appearing on the Internet. Tools are needed to help researchers understand this data. Most existing tools are geared toward batch analysis: The user formulates a query, waits for a backend engine (e.g., database or map-reduce system) to execute the query, waits for a visualization tool to render the result, and inspects the rendered result. Typically the user then formulates a new query related to the original query, and re-invokes the execute-and-render pipeline. This process continues until the user reaches a sufficient understanding of the data. Unfortunately, if the data set is large, each execute-and-render iteration takes a long time and the process is not interactive.